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HD6433846XXXH 参数 Datasheet PDF下载

HD6433846XXXH图片预览
型号: HD6433846XXXH
PDF下载: 下载PDF文件 查看货源
内容描述: 微控制器\n [Microcontroller ]
分类和应用: 微控制器外围集成电路时钟
文件页数/大小: 524 页 / 1465 K
品牌: ETC [ ETC ]
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Section 14 Power Supply Circuit  
14.1  
Overview  
The H8/3887 Series incorporates an internal power supply step-down circuit. Use of this circuit  
enables the internal power supply to be fixed at a constant level of approximately 1.5 V,  
independently of the voltage of the power supply connected to the external VCC pin. As a result,  
the current consumed when an external power supply is used at 1.8 V or above can be held down  
to virtually the same low level as when used at approximately 1.5 V. It is, of course, also possible  
to use the same level of external power supply voltage and internal power supply voltage without  
using the internal power supply step-down circuit.  
14.2  
When Using the Internal Power Supply Step-Down Circuit  
Connect the external power supply to the VCC pin, and connect a capacitance of approximately 0.1  
µF between CVCC and VSS, as shown in figure 14-1. The internal step-down circuit is made  
effective simply by adding this external circuit.  
Notes: 1. In the external circuit interface, the external power supply voltage connected to VCC  
and the GND potential connected to VSS are the reference levels. For example, for port  
input/output levels, the VCC level is the reference for the high level, and the VSS level is  
that for the low level.  
2. When the internal power supply step-down circuit is used, operating frequency fosc  
when VCC = 2.2 to 5.5 V is 0.4 MHz to 2 MHz. Otherwise, fosc is 0.4 MHz to 1 MHz.  
3. The LCD power supply and A/D converter analog power supply are not affected by  
internal step-down processing.  
VCC  
Step-down circuit  
CVCC  
Stabilization  
capacitance  
(approx. 0.1 µF)  
Internal  
Internal  
power  
logic  
supply  
VSS  
Figure 14-1 Power Supply Connection when Internal Step-Down Circuit Is Used  
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